OEM Trailer Hitch

[Skyline]

Originally Posted by upallnight

If my X didn't come with the OE hitch I would have looked at having this hitch installed.

Towbar Video - BMW X5 Westfalia Detachable - YouTube

That is pretty cool. Any idea what the cost and load rating is?

[JCL]

Originally Posted by Skyline

That is pretty cool. Any idea what the cost and load rating is?

Available from BMW dealers in the UK and Europe. There are posts on this site about those who have brought them in, those posts should have pricing info if you do a search. Load rating is same as North America, 5000 or 6000 lbs depending on year and transmission, but technically this drawbar is not legal in North America as it doesn't meet federal regulations. Ball is metric, but close to 2".

[xsx450]

I am not looking to start a raging battle. I think the OEM hitch looks heavy duty as hell and I am sure it is a better part.

I chose to go with this hitch: 2000 2006 BMW x5 x 5 Trailer Hitch Receiver Class III Reese Pro Series 51093 | eBay

$115 Delivered to your door.

Fairly simple install. You use the existing bumper bolts, and you drill a 1/2 hole into the subframe.

Rated for 6000 lbs / 600 lbs tongue weight which is all the x5 is rated for anyways.

Personally I think it is good ENOUGH. and in that degree it is great. I would never tow crazy amounts with my x5, because i love her, so to me the OEM hitch is overkill, especially if only rated the same.

Now I am not saying all of this without backup.

What I use my hitch for is hauling my dirtbike, not heavy, but quite significant tongue force. Bike weights 240lbs, it also held me and 2 other buddies jumping up and down on it. No signs of stress.










Please dont say its bending, the hauler doesnt fit 100% tight which gives it that slight angle. I have hauled like this over 20x without issue.

Just throwing that out there!

[JCL]

Originally Posted by xsx450

I am not looking to start a raging battle. I think the OEM hitch looks heavy duty as hell and I am sure it is a better part.

I chose to go with this hitch:

Glad it is working for you.

Have you calculated the bending moment being applied to the hitch? When BMW publish 600 lbs tongue weight limit they specify that the maximum load distance is 8" from the pin. Your CoG would appear to be a multiple of that, hard to tell from the pictures. Not sure what your hitch manufacturer publishes as a load limit for carriers, but it shouldn't be the same as a tongue load limit.

Also, BMW publishes a lower limit for bouncing loads, 330 lbs tongue weight. They use the lower figure for non-highway, where a load isn't always constant.

[TerminatorX5]

I am trying to figure out, why the BMW engineers have come up with SO MANY parts for the something that could have been accomplished with only one piece... They have no brain and probably suck as engineers...

[upallnight]

Different countries with different systems, example you need to buy a converter if you have electrical appliances that you want to use oversea.

UK people drive on the wrong side of the road, whereas US people drive on the Right side of the road.

This looks like the hitch that you can buy at etrailer.

[upallnight]

Originally Posted by JCL

Glad it is working for you.

Have you calculated the bending moment being applied to the hitch? When BMW publish 600 lbs tongue weight limit they specify that the maximum load distance is 8" from the pin. Your CoG would appear to be a multiple of that, hard to tell from the pictures. Not sure what your hitch manufacturer publishes as a load limit for carriers, but it shouldn't be the same as a tongue load limit.

Also, BMW publishes a lower limit for bouncing loads, 330 lbs tongue weight. They use the lower figure for non-highway, where a load isn't always constant.

His hitch has that kicker strut, so it not a pure cantilever. That bike wouldn't weight 600 lbs or even 330 lbs.

[xsx450]

Again, it is more than enough for ME. That BMW Mount looks like you are replacing a lot of the parts you already have. My mount came with grade 8 bolts, I am not worried about their shear strength. I am no engineer but I am confident using this, and would be up to the 6000 lb rating. Im not towing 12k lbs here or anything, nor ever would with my baby. me and two buddies (over 600lbs between us) with the bike, bounced on the thing at the very end, probably 18" from the hitch. Nothing happened. Its cool when the rear air suspension automatically levels though..

BMW has NEVER been known to sell ANYONE more than they needed...

[TerminatorX5]

here is the physics 101 from the NASA website... in our case only the example 1 is applicable:

A force F is a vector quantity, which means that it has both a magnitude and a direction associated with it. The direction of the force is important because the resulting motion of the object is in the same direction as the force. The product of the force and the perpendicular distance to the center of gravity for an unconfined object, or to the pivot for a confined object, is^M called the torque or the moment. A torque is also a vector quantity and produces a rotation in the same way that a force produces a translation. Namely, an object at rest, or rotating at a constant angular velocity, will continue to do so until it is subject to an external torque. A torque produces a change in angular velocity which is called an angular acceleration.
The distance L used to determine the torque T is the distance from the pivot p to the force, but measured perpendicular to the direction of the force. On the figure, we show four examples of torques to illustrate the basic principles governing torques. In each example a blue weight W is acting on a red bar, which is called an arm.
In Example 1, the force (weight) is applied perpendicular to the arm. In this case, the perpendicular distance is the length of the bar and the torque is equal to the product of the length and the force.
T = F * L

In our case, the Force is stationary for the sake of the argument and is
F = m x a (mass multiplied by acceleration).
the mass is known, 240 pounds (108.5 kg),
the acceleration is 9.8 m/s*s (earth gravity),
so our force is 1063 kg*m/s*s,
and the length of towbar is 18 inches (0.4572 m) = 486 kg*m*m/s*s = 486 N*m (not to confuse with 486 joules, which is the energy resulted from the same calculations)...

naturally, the longer the towbar, the greater the "lever" effect...

1 Nm = 0.7375621 lbs*foot
486 Nm = 358.46 lbs * foot (or, more common term, "foot-pound)

so, in the stationary condition, we are applying a torque of roughly 350 pound foot onto the hitch bar and the hitch assembly.

Once we introduce the additional forces of driving forward and bouncing the load vertically, the numbers will decrease on "up" and increase on "down" move, also, as the vehicle is moving on the decline, the torque will decrease, as if the vehicle is moving on the incline, up the hill, the center of bike's gravity will move further away from the 18" mark and the torque will increase...

I am just too lazy to venture into these calculations...

The main point is, will the mounting points sustain the load, and more importantly, will the places where they are mounted to, sustain the load... those items can be calculated, based on the type of metal used, the thickness of the metal, the type of the attachment of different materials, the ability of the metal to take the repeating bending stress without losing the resistance property and the metal fatigue that will eventually settle in the material before anything would break.

These are the calculations taken into the account by the engineers who design these things...

Remember the Fast 5 movie - when Dominique Torreto and Co. ripped the "unbreakable" safe from the enclosure, as the enclosure was not reenforced enough to protect the vault... so, it did not matter that the vault was good, the surroundings weere not up to par...

oh, and by the way, I am not here to rain on your parade - I am in engineering myself, and can only appreciate a well executed mechanical (or electrical/electronic) masterpiece... And I think, the OE tow hitch is an engineering masterpiece...

[xsx450]

I wish my 6-speed transmission was an engineering masterpiece!!!

That said it does shift very nice and i do enjoy everything about the way it works...